One month after Osama bin Laden's death: a schoolboy rides on the back of a van in Abbottabad, on the road leading to the compound where the al-Qaida leader was killed. Photograph: Warrick Page/Getty Images

Just outside Islamabad, on the airport road, visitors to Pakistan are welcomed by an eyecatching monument to awesome power and destruction: a model mountain.

It represents the remote Chagai Hills where 13 years ago Pakistan exploded its first atomic device, signalling its entry into the global nuclear elite. Since then the country's stockpile has swelled, amid great secrecy and expense, to more than 100 warheads – the world's seventh largest.

The nukes are a powerful deterrent against arch-rival India, of course, but they are much more too: a source of immense pride, and a symbol of the prowess of the army, the institution that has controlled Pakistan's destiny, directly and indirectly, for most of the past six decades. At night, when the Chagai model lights from inside with a fiery glow, patriotic parents bring their children to pose for photos.

Yet since the death of Osama bin Laden on Pakistani soil exactly one month ago, Pakistan's great fissile firepower has appeared curiously impotent, as the military reels before a cascade of crises that underscore weakness, not strength. The generals face accusations they cannot protect the country's borders, its military bases or their own street bruisers.

First there was the humiliation of the American raid to kill Bin Laden. The army had to admit that 47 US navy Seals, flying in five helicopters, could slip into the country, carry out a violent 39-minute raid in a garrison town, then escape entirely unhindered with the body of the world's most wanted man. Then came the bloody retaliation from an energised Taliban: a series of suicide bombings that killed more than 150 people, most of them soldiers.

Last week, Pakistanis were aghast at the sight of a small team of well-trained militants who stormed Karachi's Mehran naval base, blew up two sensitive surveillance aircraft, and held commandos at bay for 17 hours. Then this week, a body: journalist Saleem Shahzad, dumped in a canal with torture marks, a day after he disappeared. Outraged colleagues and human rights workers say his greatest fear was abduction by the army's Inter-Services Intelligence (ISI) agency, which now faces a storm of angry criticism, although it has denied any involvement.

The cascade of misfortune has triggered an emotional reaction – despair, fury, denial – and more self-reflection than usual in a country that is perpetually grappling with questions of state, ideology and national cohesion. "A generation ago, [Salman] Rushdie wrote a book on Pakistan called Shame," tweeted the blogger @theselongwars. "We need a new book called Shameless."

Most of the heat has focused on the army. In parliament, angry politicians fired questions at top generals; one even complained to the ISI chief, General Shuja Pasha, that he had been tortured by intelligence men under the regime of President Pervez Musharraf. Television stations have carried unusually harsh criticism of top generals, about their tactics, their intelligence and even their lifestyles. Firebrand lawyer and human rights campaigner Asma Jahangir caused a sensation by delivering a television tongue-lashing against "duffer" generals who, she said, were more interested in running wedding halls than defending their territory.

Even conservative politicians have found their tongues. "Previously, security matters in Pakistan were considered very holy, too sacred to be dictated," said Ahsan Iqbal, a senior figure in opposition leader Nawaz Sharif's party. "Now people are asking questions."

More significant, perhaps, is the anger inside the army. After the Bin Laden raid the normally imperturbable army chief, General Ashfaq Kayani, held town-hall meetings on three bases. According to a senior general and several diplomats, he faced a flurry of disgruntled queries from his own men, most of whom were furious with what they saw as American betrayal.

One diplomat who met Kayani recently said he was "angrier and more upset than I've every seen him before, because he's getting a rough ride inside the military." He added: "I don't think he's in a comfortable place."

To appease such sentiment, the military has cut back on co-operation with the US, sending home dozens of military trainers and slashing back some programmes. Relations between the ISI and the CIA have hit rock bottom. But distrust is equally growing in America, where, in the aftermath of the Bin Laden raid, Pakistan has become a byword for treachery and clumsy deception – even on the comedy stations.

"The Pakistani military could have caught Osama with a rod and reel, or a giant Acme magnet," joked Jon Stewart; on Jay Leno's show a song about Bin Laden had the punchline: "Pakistan: where the government will protect me." Angry congressmen, meanwhile, are clamouring to slash the $3bn (£1.83bn) annual aid it gives to Pakistan. "We cannot continue to send money to people that are not dealing with us fairly," said Allen West, a Republican from Florida, on Fox news.

Despite the stinging accusations, US officials say they have uncovered no proof of Pakistani complicity with the al-Qaida leader. One leaked document from his house suggests the opposite is true: that Bin Laden sought an alliance with Pakistan a year ago, meaning that he lacked one, at least until then.

Establishing the facts has always been difficult in Pakistan, where cynicism is a creed and conspiracy theories as popular as sweet milky tea. According to one poll, a majority of Pakistanis believe the Bin Laden raid was a US charade. After the Karachi naval base assault, convoluted theories went around, many spread by retired generals on television, that the debacle had been secretly orchestrated by Indians, Israelis or Americans to destabilise Pakistan and snatch its nuclear weapons.

Yet some facts now loom, hard and unavoidable. Many inside Pakistan recognise that the blowback from jihad – covert support for Islamist groups in Afghanistan and India – is in full effect. Former "assets" have turned on their masters, unleashing bloody mayhem across the country. And the spectre of radicalisation inside the ranks raised its head again on Monday, when military intelligence detained a former naval commando accused of helping with the attack on Karachi's Mehran base.

Meanwhile in the US, the trial of an accused Lashkar-e-Taiba operative has produced a stream of embarrassing allegations linking ISI officers to the 2008 Mumbai attacks. And the ISI chief Pasha is hiring lawyers in New York to defend him against similar accusations in a lawsuit.

The internal "double game", in which Pakistan's leaders have attempted to fool their own people, is also collapsing. Loud protestations against CIA drone strikes in the tribal belt seem meaningless since a flurry of WikiLeaks cables, some released a few weeks ago, showed how the army chief and prime minister quietly supported American actions.

For many Pakistanis, the very notion of sovereignty has become confused. "The sky is dark with the chickens coming home to roost in Pakistan," said the US academic and Pakistan expert Stephen Cohen.

If the 9/11 attacks opened the previous chapter of US relations with Pakistan; Bin Laden's death has opened a new one. What it contains is deeply uncertain. British diplomats are scrambling to midwife a reconciliation between Washington and Islamabad, largely out of self-interest: anti-western antagonism will hurt ISI co-operation with MI6, seen as crucial to warding off attacks in Britain.

There are some gentle signs of progress: the army has allowed CIA access to Bin Laden's abandoned house, and returned the tail section of a destroyed US stealth helicopter. Speculation is rising that Pakistan will launch a summer offensive on the al-Qaida headquarters of North Waziristan – although Pakistan's generals denied it on Wednesday.

Still, impatience is swelling in Washington. Next month General David Petraeus, the army commander who has been hammering the Taliban leadership in Afghanistan with controversial night raids, takes over at the CIA. Drone strikes – the main irritant in relations – are unlikely to decrease.

"It's very hard to predict what's going to happen; too many variables are moving in different directions," said Cohen.

Other worrisome issues bubble in the background. The economy is in freefall, propped up only by international aid; the delinquent electricity system is semi-collapsed, with some places enduring 14-hour power cuts in 40C heat. Street protests are likely over the summer, although few expect them to produce an Arab-style revolution. Pakistan's people are divided by class, ethnicity and region; there is no obvious Mandela figure waiting in the wings. Instead there is much talk of "honour" – two weeks ago Sharif's party ended American aid to Punjab, the country's largest province by population, in protest at the Bin Laden raid. As one western official put it, "emotion is battling with logic."

The crucial question in Pakistani politics is the balance of power between the military and civilians. Whether the past month has changed that is unclear, but experts are sceptical. "The military has suffered a huge blow to its prestige," said Cyril Almeida of Dawn newspaper. "But that won't necessarily translate to permanent disillusionment. If the army plays its cards right, people will soon be rallying behind 'our boys'."

Predictions of a larger collapse, frequently made in Pakistan, have always been wrong. Once the emotion of the Bin Laden aftermath has passed, the country will likely resume on its previous path, stumbling forward. "Strategy is very un-Pakistani," noted one western official. "You kick the can down the road and hope it lands in the right place."

Yet there is an undeniable sense that the country is vulnerable to another wildcard event: a terrorist spectacular in India or America, the assassination of a leader, or even a real militant threat to the nuclear bombs. With so many problems spinning at once, Pakistan has become a place where anything can happen, and frequently does.

The last wildcard, however, was bequeathed by Bin Laden himself. At CIA headquarters US officials are frantically combing a trove of al-Qaida computer disks seized from his hideout.

It is a Pandora's Box of intelligence. Will it produce fresh leads on al-Qaida? Evidence of Pakistani collusion or innocence? Or the impetus for a fresh drive against Bin Laden's network? Whatever the case all roads, it can be assumed, will lead to Pakistan.

• This article was amended on 2 June 2011. The original described Punjab as Pakistan's largest province. This has been clarified.